OK, and so that means you can’t say 1 bad thing about China?

You can. You've already done it, several times in fact. Don't focus on can, focus on should. Where does this urgent desire to say bad things about the PRC come from anyway? What I'm really asking you is: When you exercise your speech, what do you hope to accomplish by saying PRC is bad sometimes? Who are the people you hope understands and agrees with you that the PRC is bad sometimes? What do you think is most likely to result from you saying that the PRC is bad sometimes?

But I don’t understand why a leftist shouldn’t be able to bring up the number of billionaires in China, for example, when talking to other leftists without being labeled as some sort of traitor or propagandist or some other dumb bullshit. “They have less and more regulated billionaires than the U.S.” – yeah, I think that’s awesome, I would still prefer if billionaires didn’t exist though. And me saying that doesn’t mean I’m equating China to the U.S.

Why should you bring it up in the first place?

Or human rights – yeah, I know and constantly criticize the U.S. on their human rights violations – what kind of hypocrite would I be if then I stay silent or just says “well, the U.S. is worse” when China is brought up. Fuck that.

You would indeed be a hypocrite if you believed that the PRC was a particularly egregious offender of human rights or are anywhere near the level of the US. Do you?

Leftists that don’t support American/western bullshit should absolutely have a right to level reasonable criticism towards China or any Marxist country.

Sure. Make sure it is constructive though. To make a constructive effort in criticizing, you should be taking your concerns to the CPC itself, built on an educated foundation and with viable solutions taking into account the material conditions. What you've been doing so far has been complaining to us. Congratulations, you've felled a tree in the forest while the CPC was away in the city. There are 2 ways this criticism can go. You can go tell the CPC that you've felled the tree, or you can fashion a spear from the bark of the tree with which to stab the CPC with (destructive criticism). This latter thing is what the libs/China watchers do btw, which is complain to Big Brother (US gov) so that he hurts (regime change) that meanie (PRC) over there. We socialists actually do the same thing but with regards to the US instead: complain to Big Brother (US masses) so that he hurts (revolution) that meanie (US gov) over there. Why? Because we seek its destruction, hence destructive criticism, just as the libs seek the destruction of the PRC. Now apply this logic to when the left sets its sight on the PRC and does what you're doing. Can you see why I'm your questioning your intentions?

Because you’re allowed to criticize stuff you support dude. What, if China tomorrow started, I don’t know, killing gay people for example, should I just not talk about it ever?? Come on, don’t be such babies.

This is not a reason and you probably know it already. This is just doing it for the sake of doing it. I didn't ask whether or not you were allowed to do whatever. You spent so much time wondering if you could, you never stopped to think if you should. Again, when you exercise your speech, what do you hope to accomplish by saying PRC is bad sometimes? I want to know why you just HAD to let us know that the PRC is bad sometimes, when "PRC isn't perfect" has probably been repeated a million times in every defense ever made at this point.

Or if you have a friend that you love and support, is it a sin to criticize them or call them out when they’re doing something bad?

No, but in this scenario, you actually have the power to do a constructive critique. Because here you have a better understanding (educated foundation) of your friend and you're more aware of their material conditions and can hence come up with proper solutions. Most importantly, you are talking to them directly and not rallying a group of bullies to denounce your friend. The citizens of the PRC are in this position whilst you on an online forum in the heart of Empire are not.